Both American and European engineers continued to work n the problems of designing practical craft. Not until early 20th century was a hovercraft possible because only the internal combustion engine had the very high power to weight ratio suitable for hover flight.
The commercially viable model of a hovercraft was designed in by the English inventor Christopher Cockerell. It's different from traditional vehicles because it has no surface contact when it's in motion. Since then, many types of land, marine and amphibious air cushion vehicle have developed.
Hovercraft has paved its way for new opportunity on Malaysia manufacturing sector. Its major introduction is to assist fire and rescue department and was produced by AFE manufacturing company with Japanese technology collaboration.
The working model hovercraft must perform basic function of hovercraft and able to travel on water surface. This model must able to produce enough air cushion to hover its body and also can lift some loads.
The hovercraft must able to produce enough thrust to move along the ground by itself and with some loads. Figure 1. Propulsion is not derived from contact with the water or the ground. Skirt is fixed in the craft perimeter, holds and keep enough air mass and pressure beneath the hull granting it to be away from surface, it must be flexible and contour surface irregularities and waves and be water and air proof.
The primary goal is to prepare a full drawing of preliminary design of small hovercraft. The principal dimension of hovercraft is depending on their ability to support the determined payloads. This hovercraft model is for study and research purposes while still perform its basic functions.
Thus, it must have all the required characteristics of the hovercraft even this is a small scale model. The hovercraft will be fabricated with polystyrene or Styrofoam This hovercraft will use dual power plant engines or electric motors for thrust and lift systems. Because of their consumption for this craft to lift some loads, high speed engine or motor is applied to the lift power.
Lift power should be controllable to get sufficient pressure in the cushion and suited with the applied loads. Skirts materials must flexible and has sufficient stiffness so that it can operate on water surface. The first chapter is discussing about the introduction of the topic followed by the theory, and literature review will be in chapter two. Discussion and explanation of the research methodology for all the methods and the components that require for mechanical design will be in chapter three.
In chapter four, the contents are about the results and discussion for the project. Last but not least, the conclusion and recommendation for the project will be in the chapter five. Nowadays there are several types of hovercrafts, but a definition of a hovercraft can still be given: A hovercraft is a self-propelled vehicle, dynamically supported by a self generated cushion of slow moving, high-pressure air which is ejected against the surface below and contained within a flexible "skirt" such that it is totally amphibious and has some ability to travel over less than perfect surfaces.
Propulsion is not derived from contact with the water or the ground [1]. A hovercraft is one of the children of the air cushion vehicle ACV family that flies above the earth's surface on a cushion of air. It is powered by an engine that provides both the lift cushion and the thrust for forward or reverse movement. The hovercraft child is a true multi-terrain, year-round vehicle that can easily make the transition from land to water because it slides on a cushion of air with the hovercraft skirt and only slightly brushes the surface.
In its simplest form, a hovercraft is composed of a hull that can float in water and is carried on a cushion of air retained by a flexible 'skirt'. Hovercraft are boat-like vehicles, but they are much more than just a boat, because they can travel over not only water, but grass, ice, mud, sand, snow and swamp as well. A hovercraft is a craft that has little to no friction, and does not touch the ground.
There are two methods of lift which are ground effect and seeping pressure. The ground effect is caused by blowing air at the ground, creating a higher pressure below the fan than above the fan, forcing the craft upwards. This is inefficient in comparison to a pressure based craft, since the pressure between the fan and the ground is easily dissipated to the sides.
The more efficient way to have a craft hover is to create a higher pressure under the skirt in comparison to the ambient pressure. This would create a force on the air to move from the high pressure, under the craft, to the lower pressure, outside the craft. Cockerell discovered that by means of generating a wall curtain of high-speed downward-directed air around the edges of a hull, that less air leaked out from the sides due to the momentum of the high-speed air molecules , and thus a greater pressure could be attained beneath the hull.
Some hovercrafts use a single engine system to provide both the air for the plenum chamber and propulsion. The difficulty in using one engine is to provide optimal efficiency for both systems, dividing the power for propulsion as well as for the fan to produce enough air for the lift.
Many modern air cushion vehicles use separate systems for air and propulsion. But advances in engines have made it possible to choose between one and two engine systems, especially for smaller, recreational hovercraft. Bigger, industrial, commercial or military hovercraft can have anywhere up to eight engines for propulsion and lift. The greater this ground clearance the more efficiently the propulsion system operates. That is not to say that the higher the hovercraft lifts into the air the better.
Lifting it too high will cause instability. The power-to-weight-to-strength ratio deals with the structural strength of the craft to be light enough to be lifted by the air cushion created underneath, yet strong enough to carry the weight of the engine, its passengers or payload.
Air cushion vehicle hull construction is more closely based on aviation rather than marine constructions for the simple reason that aviation hulls are a combination of strength and lightness as opposed to strength as a priority. Although wood and plywood are often used, many hovercraft hull structures are made of aluminum skin, welded or riveted onto an aluminum web or frame.
Enclosed spaces are sealed to provide airtight compartments for natural buoyancy. Learn how your comment data is processed. Introduction to Pressure Vessels Vessels, tanks, and pipelines that carry, store, or receive fluids are called pressure vessels.
A pressure vessel is defined as a container with a pressure Knuckle Joint A knuckle joint is used to connect two rods which are under the action of tensile loads. However, if the joint is guided, the rods may support a compressive load. A knuckle joint Skip to content Home - Blog - Mechanical Seminar. Table of Contents. Introduction To Hovercraft : A Hovercraft is a vehicle that, Flies like a plane but Float like a boat Drive like a car It can hover over or move across land or water surfaces while being held off from the surfaces by a cushion of air.
A Hovercraft is a vehicle that flies like a plane but can float like a boat, can drive like a car but will traverse ditches and gullies as it is a flat terrain. A Hovercraft also sometimes called an air cushion vehicle because it can hover over or move across land or water surfaces while being held off from the surfaces by a cushion of air.
A Hovercraft can travel over all types of surfaces including grass, mud, muskeg, sand, quicksand, water and ice. Modern Hovercrafts are used for many applications where people and equipment need to travel at speed over water but be able load and unload on land. Air and other gases can also be used, This detailed book delves into the history of the hovercraft, from the early days of its development through to the commercial and military applications of the craft.
You will also need some string and a supply of weights. Tape one end of the string to Panayi Marine Road, Morecambe, The hovercraft Sir, — There has been a considerable amount of publicity given to the hovercraft , its principles and mode of operation but nowhere have I read any reference to the possibility of its The U.
Squadron Leader D. Letham R. Interservices Hovercraft Unit, HMS Daedalus' My paper concerns the role which we, at the Interservices Hovercraft Unit, think that hovercraft can play in disaster situations in coastal areas. Example 7. If the hovercraft is moving It was for these reasons that the certification of the design and construction of hovercraft and the supervision of maintenance had been Pull Ahead Books. Minneapolis : Lerner , Jackson , Kevin.
Discover the Hovercraft. Sautter , Aaron. Mankato , Minn. Picture a sky full of hovercrafts above every major city. Manny is right. This is not just some invention that people will use in their own spaces.
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